Wheel slip prevention mechanism for locomotives



C. K. STEINS April 20, 1948.

WHEEL SLIP PREVENTION MECHANISM FOR LOCOMOTIVES Filed April 30, 1945 3 Sheets-Sheet 1 8 m1 3 V0 m \N .Sm Ne WITNESSES ATTORNEYS.

April 20, 194 K, STE 2,440,124

WHEEL SLIP PREVENTION MECHANISM FOR LOCOMOTIVES Filed April 30, 1945 3 Sheets-Sheet 2 HGLZ.

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April 20, 1948. c. K. 'STEINS 1 2,440,124

WHEEL SLIP PREVENTION MECHANISM FOR LOCOMOTIVES I Filed April 30, 1945 3 Sheets-Sheet 3 WITNESSES INVENTOR:

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ATTORNEYS.

Patented Apr. 20, 1948 2,440,124 WHEEL SLIP PREVENTION MECHANISM FOR LOCOMOTIVES Carleton K. Steins, Merion, Pa, assignor to The Pennsylvania Railroad Company, Philadelphia, Pa., a corporation of Pennsylvania Application April 30, 1945, Serial No. 591,134

This invention relates to mechanism useful in connection with steam locomotives to prevent slippage between separately powered groups of driving wheels. I

Experience in the operation of locomotives has determined that the back pressure of the exhaust steam increases in direct proportion with the engine and wheel speed. Thus, in a multiple engine locomotive, increase in the speed of one group of powered driving wheels over that of another such group due to slippage will result in a pressure differential f the exhaust from the several engines.

The chief aim of my invention is to provide mechanism in which such difierential is utilized to automatically effect a reduction in the supply of steam, or the complete shutting off of the supply of steam, to the engine of theslipping wheels and so prevent them from racing until normal running conditions are reestablished or restored.

A further aim of my invention is to secure the above desideratum with automatic mechanism which is simple and inexpensive; which is highly sensitive and positive in its action; and which can be applied to existent locomotives at relatively small expense without requiring any radical changes in them or interfering with their usual mode of operation.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings, wherein Fig. 1 is a diagrammatic view in perspective of a multi-englne locomotive with wheel slipprevention mechanism conveniently embodying my invention.

Fig. 2 is a fragmentary view in elevation on a larger scale of a pneumatically actuated live steam valve unit of which several are employed in the mechanism; with a portion of the unit broken out to expose certain internal parts which would otherwise be hidden.

Fig. 3 is an axial section of the valve unit looking as indicated by the angled arrows III-III in Fi 2.

-Fig, 4 is a cross section taken as indicated by the angled arrows IV -IV in Fig. 2; and

Fig. 5 is a view likewise drawn to a larger scale of a difierential cylinder and adjacent parts which are relied upon to control the supply of compressed air to'the several pneumatically actuated steam valve units, said cylinder being shown in axial section.

In these drawings I have shown my invention I as embodied in a locomotive, which, see Fig. 1, 55'

4 Claims. (Cl. 105-48) has two sets of plural side rod-connected driving wheels l5 and I6 actuated by cylinders l1 and I8 at opposite sides of the locomotive. Live steam is delivered to the cylinders l1 and ill from the boiler (not shown) of the locomotive through conduits 20, 2|, and the exhaust steam conducted from said cylinders through conduits 22 and 23.

The mechanism provided in accordance with my invention for automatically apportioning the supply of live steam to the cylinders I1 and IS in order to prevent slippage between the separately powered drivers l5 and I6 includes pneumatically-operable valve units 24 and 25 of which one is interposed in each of the live steam delivery pipes 20 and 2! and of which one is separately illustrated in Figs. 2-4. The compressed air utilized in the system is stored in a reservoir 26 and conveyed through a pipe 21 having extensions 28 and 29 with branches 30 and SI which lead directly to the individual steam valve units 24 and 25. Normally-closed air valves 32 and 33 interposed in the pipe extensions 28 and 29 are actuated in a manner later on explained herein by the piston rod of a differential cylinder 35 which is shown in detail in Fig. 5. Connecting into the side of the cylinder 35, at points adjacentits opposite ends, are pipes 36 and 31 with branches 38 and 38 which extend from the exhaust conduits '22 and '23 ofthe engine cylinders l1 and Hi.

Check valves shown at 40 and 4| serve to prevent back flow of exhaust steam from the differential cylinder 35, said valves having small bleed orifices 40a, 4 la in their closures or gates.

Referring to Figs. 2-4, it will be noted that each valve unit 24 (25) includes a butterfly closure vane 46 with its diametral shaft 41 extending crosswise of the live steam" conduit 20 (2|) and journaled at' its ends in-replaceable bearings :48Yat the opposite sides of the conduit, said bearings being accessible upon removal of thescrew phigs shown at 49. By means of a lin 50:.extending through a lateral clearance opening 5 l in the conduit 20 the vane 46 is connected to the diametrically reduced extension 52 of a piston 53 disposed within a cylinder 54 at one end of a casting 55. As shown this casting 55 has'a flange 56 at its opposite end for application over the opening 5| in the conduit 20 (2|) by means of screw bolts 51 passingthrough said'fiange and a mating 'fiange 58 on said conduit. As further shown, one of the compressed air supply pipe branches (in this instance'the branch "30), nects with a central port 59in the head filljofthe cylinder 54; The extension 52 of the' piston'f53 passes through a guide'boss SI of the casting 3 55 which is integrally united with the cylinder 54 by a yoke 82. As shown the piston extension 52 is surrounded by packing 83 compressed by a gland 85 which is retained by nuts 88 threadedly engaging the endsof stud bolts 51. At 88 is indicated a relief nipple which has an orificed diaphragm 89 and which communicates with a small port open into the clearance space between the piston 53 and the cylinder head 68. Connecting laterally into the cylinder 54 forwardly of the piston 53 is an outlet ll through which accumulated condensation may be drained irom time to time, as may be necessary, under control of a petcock 12. The apertures at 13 permit pressure equalization to take place between the cylinder 54 and the hollow of the piston rod extension 52. The vane 46 of the steam valve unit is normally in the open position in which it is shown, its swing toward closed position in the direction of the arrow in Fig. 2 being limited by a stop projection 14 at the inside of the conduit 28 (2|).

By reference to Fig. 5, it will be noted that the differential cylinder 35 has a central partition 15 and is closed at opposite ends by screw cap heads 16. Located within the end chambers l1 and 18 set apart Within the cylinder 35 by the partition 15 are pistons 19 and 80 which are rigidly secured against spaced shoulders on a connecting rod 8| by nuts 82, the diametrically reduced ends of' the rod 8| extending outward through the hollow central bosses of said cylinder heads. The pistons 19 and 80 normally occupy the positions in which they are shown, being so yieldingly maintained by helical compression springs 83. At one end each spring 83 abuts its piston, while its other end bears against the bottom of a socketed plug 85 threadedly engaged in the corresponding head 16. By adjusting the plugs 85, it is possible to regulate the force of the springs 83 as may be desired or required, the adjustments being fixable by means of lamb nuts 86. Adjustable on the outer ends of the piston rod 8! are abutment heads 81 for contacting the slide stems 88 of the valves 32, 33 to open them in a manner presently explained. The diflerential cylinder 35 is relieved at opposite ends by way of apertures 89 in the heads 18 as well as by way of clearances 98 around the stem ends within the plugs. Leading from the chambers 11 and 18 of the differential cylinder 35 are pipes 8! for connection of pressure gauges 32, or other indicating means, these being preferably disposed in the cab of the locomotive for convenience oi observation by the engine crew.

The operation of the mechanism is as follows: Let it be assumed for example that slippage of the forward drivers i5 of the locomotive is taking place, with attendant increase in the amount of the steam exhausted from the ensine cylinders I! by way of the conduits 22 and building up of the pressure in the piping 38, 38 leading to the chamber 11 of the differential cylinder 35. As a consequence of the increased pressure on the piston 19 the piston rod 8| will be moved to the right in Fig. 5 and cause the air valve 32 to open. This'action will be gentle over a short time interval determined by the size of the orifices 88 in the right hand cylinder head I8. Opening of the air valve 32 as Just explained will allow compressed air to flow from the reservoir 28, byway of the piping 21, 28 and 30, to the operating cylinders 54 of the steam supply valve units 24. Accordingly, the piston 53 or these valve units 24 will be moved forwardly in the cylinders 54 to swing the vanes 48 in the conduits 28 in the direction of the arrow in Fig. 2 toward closed position with the result that the supply of live steam to the cylinders II will be reduced or shut oil completely to prevent spinning of the drivers l5. When this occurs the pressure in the piping 36, 38 will immediately drop and tend to reverse the movement of the piston rod 8i of the differential cylinder 35, but sudden reversal is prevented by the cushioning action resulting from slow release of the trapped exhaust steam from the chamber 11 of the differential cylinder 35 by way of the small bleed orifice 40a in the gate 01' the check valve 40. As the piston rod 8| of the differential cylinder 35 returns to its normal position theair valve 32 is allowed to close and shut off the compressed air supply to the operating cylinders of the steam valve units 24, whereupon the live steam in. the conduits 20 in acting on the exposed ends of the extensions 52 of the pistons 53 of said units will cause the latter to re cede and swing the butterfly vanes 48 back to open position, as the air is gradually exhausted from the cylinders 54 by way of the bleed nipples 68. My improved slip preventio mechanism is thus both smooth and positive in its action.

The action of the mechanism upon slippage of the drivers I6 will be analogous to that above described except that in this case the piston rod of the diilferential cylinder 35 would be moved leftward in Fig. 5 to open the air valve 33 for release of compressed air to the steam valve units 25 of the corresponding engine.

While for convenience of exemplification herein, I have shown and described my invention in connection with a reciprocating engine steam locomotive, it is to be understood that its use is not limited to use with this type of locomotive, since by suitable modifications within the scope of the appended claims it can be readily incorporated in turbine driven locomotives without sacrifice of any of the advantages hereinbeiore pointed out.

The term engines as used in the claims is accordingly to be construed as including not only cylinder engines and turbines but other types of steam actuated prime movers as well. Furthermore the expression groups is to be regarded as comprehensive of an axle-connected pair of drivers or several of such pairs.

Having thus described my invention, I claim:

1. Slip prevention mechanism for a steam locomotive having two groups of driving wheels powered by separate engines, and separate conduits respectively for conducting live steam to and exhaust steam from said engines, said mechanism including normally open control valves respectlvely in the live steam conduits; a pneumatic operating cylinder with a piston therein connected to the closure member of each steam control valve, said piston having a diametrically reduced portion with its end exposed in the corresponding live steam conduit; a source of compressed air; normally closed air valves interposed in piping extending from the air supply source to the operating cylinders of the control valves of the respective live steam conduits; and means responsive to the diil'erential in the back pressure of the exhaust from the two engines for opening theair valve corresponding to the engine of the slipping wheels and delivery of com ressed air to the operating cylinder of the corresponding steam valve for movement of the latter toward closed position to reduce the steam supply to such engine until normal running conditions are restored.

2. Slip prevention mechanism for a steam locomotive having groups or driving wheels powered byseparate engines and separateconduits for delivering live steam to the several engines; said mechanism including individual flow. control means in said live steam conduits, pressure fluidactuated devices for operating the live steam control means, normally closed valves interposed between said devices and a supply source of pressure fluid at a pressure higher than that of the exhaust steam, and means responsive to the difierential in the back pressures of the exhaust from the several engines upon slippage of any of the wheel groups and automatically operative to open the valve of the pressure fluid device for the steam control means of the engine of the slipping wheels, thereby to effect a reduction in the steam supply to such engine until normal conditions are restored.

3. Blipprevention mechanism for a steam locomotive having two groups of driving wheels powered by separate engines, and separate conduits respectively for conducting live steam to and exhaust steam from said engines; said mechanism including normally open steam flow control means respectively in the live steam conduits each comprising a closure member and an operating cylinder with a piston therein having a large end and a diametrically reduced end which is exposed in the corresponding live steam conduit, normally closed valves in pipes extending from a pressure fluid supply source to the respective operating cylinders, and means responsive. to the diflerential in the back pressure of the exhaust from the two engines and operative to open the pressure fluid valve corresponding to the engine of the slipping wheels ior delivery of pressure fluid to the large end of the piston in the operating cylinder of the corresponding steam control means whereby the closure member of the latter is moved to reduce the steam supply to such engine until normal running conditions are restored.

4. Slip prevention mechanism. according to claim 2, for a steam locomotive with two groups of driving wheels powered by separate engines, wherein the differential means comprises a cylinder having chambers at opposite ends thereof in communication with the exhaust steam conduits of the respective engines, individual pistons within the respective chambers of the cylinder aflixed to a piston rod that protrudes beyond the opposite ends of the cylinder and reaches to the normally closed valves, and means ioryieldingly resisting movement of the piston rod in either direction from a normal neutral position. r

CARLE'ION K. S'I'EINS.

REFERENCES CITED The following references are of record in the. 

